Store cards that charge interest at 25% a year or more will have to tell customers on their statements that cheaper credit is available elsewhere.

The move is being introduced by the Competition Commission (CC) to help prevent store card holders from being overcharged. The CC calculated that store card users have been overcharged by £55m a year.

“Some store cards are nothing less than exorbitant,” said financial adviser Martin Cunningham.

“A lack of competitive pressure on their rates means they charge pretty well what they like and that situation is at last being addressed – and nor before time in my book.”